Refrigerator



Nov. 18, 1969 TETSUYA KOHYA ET AL 3,478,536

REFRIGERATOR Filed July 24, 1967 s Sheets-Sheet 1 i ww m m ,22 l 64 n LI i 1 -26 9H 2a 36 54 /60)62 Nov. 18, 1969 Filed July 24. 1967 TETSYUYAKOHYA ET AL 3,478,536

REFRIGERATOR 3 Sheets-Sheet 2 Nov. 18, 1969 TETSUYA KOHYA ET AL.3,478,536

REFRIGERATOR rs sheets-sheet 3 Filed July 24, 1967 Fig.5.

m Q mn United States Patent US. Cl. 62-441 Claims ABSTRACT OF THEDISCLOSURE In order to store refrigerated food, a thermally insulatingcase with a thermally insulating lid is disposed Within an evaporator ofthe usual construction. The case is provided with a plurality of ventson each of the upper and lower portions of each side wall with the uppervents having a diameter tapered from the interior toward the exterior ofthe case to cause warm air to easily leave the case while the lowervents have a diameter tapered from the exterior toward the interior ofthe case to cause cooled air to easily enter the case. Also a space isprovided between the bottom walls of the case and evaporator or betweenthe upper wall of the evaporator and the inner top wall of therefrigerator housing for receiving ice-making trays.

The invention relates to improvements in refrigerators.

In the conventional type of refrigerators adapted to store refrigeratedfood therein, it has been commonly practiced to dispose a thermallyinsulating partition in the form of a hollow rectangular prism upon theupper surface of an evaporator to form a space providing a freezing orrefrigerating chamber therebetween. Alternatively an evaporator could bemade in the form of a hollow rectangular prism of which interior itselfis utilized as a refrigerating chamber. In either case refrigerated foodis adapted to be disposed directly onto the surface of the evaporatorand therefore it is able to be stored at low temperatures during acooling operation. However, during a defrosting operation and especiallyduring a defrosting operation performed either by the hot gas systemutilizing a gaseous refrigerant at a high temperature from theassociated compressor or by a heater system utilizing heat generated bythe associated electric heater, the evaporator abruptly increases insurface temperature. This may lead to a fear that the refrigerated foodstored in the refrigerating chamber will be thawed out; To avoid thisfear it is necessary to remove the refrigerated food from therefrigerating chamber during the defrosting operation each time it isperformed. This requires the user to expand additional labor.

Also there have been previously known refrigerators of the type in whichif refrigerated food is kept stored the cooling operation continued tobe performed with the associated defrosting mechanism remaininginoperative. This measure results in an increase in the amount of frostformed on the exposed surface of the evaporator greatly decreasing thecooling efliciency thereby to increase the temperature within therefrigerator.

Accordingly it is a general object of the invention to eliminate theabovementioned disadvantages of the conventional refrigerators.

It is an object of the invention is provide a refrigerator of the typeincluding an improved thermally insulating case for storing refrigeratedfood while preventing it from melting in the operation of defrosting theassociated evaporator.

It is another object of the invention to provide a refrigerator of thetype described in the preceding paragraph 3,478,536 Patented Nov. 18,1969 including a space in which at least one ice-making tray is disposedin contact with the associated evaporator.

Briefly, the invention accomplishes the above cited objects and otherobjects which become apparent as the description proceeds, by theprovision of a refrigerator comprising a housing assembly including anouter housing, an inner housing disposed within the outer housing toform a closed space therebetween, and a thermally insulating materialfilling the space. The inner housing has a front open face, a thermallyinsulating door for opening and closing the front open face, and anevaporator in the form of a hollow rectangular prism is disposed withinsaid inner housing to form a cooling system along with a compressor anda condenser. A thermally insulating case composed of a thermallyinsulating material in the form of a hollow rectangular prism isprovided and has a front open face and a bottom surface, and a thermallyinsulating lid for opening and closing the last-mentioned front openface thermally insulating case along with the thermally insulating lidin its closed position provides a refrigerating chamber for storingrefrigerated food.

Preferably at least one ice-making tray may be disposed between theouter bottom surface of the thermally insulating case and the bottomwall of the evaporator.

The invention will become more readily apparent from the followingdetailed description taken in conjunction with the accompanying drawingsin which:

FIGURE 1 is a schematic front elevation view of a refrigeratorconstructed in accordance with the principles of the invention with itsdoor open.

FIGURE 2 is a longitudinal section view taken along the line IIII ofFIGURE 1 as viewed in the direction of the arrows with the door closed;

FIGURE 3 is a fragmental cross section view taken along the line IIIIIIof FIGURE 1 as viewed in the direction of the arrow;

FIGURE 4 is a fragmental front elevation view of a refrigeratorillustrating another embodiment of a thermally insulating caseconstructed in accordance with the teachings of the invention with partsbroken away;

FIGURE 5 is a cross section view taken along the line V--V of FIGURE 4as viewed in the direction of the arrows;

FIGURE 6 is a plan view, partly in section of a modification of theinvention;

FIGURE 7 is a sectional view taken along the line VII-VII of FIGURE 6;and

FIGURE 8 is a sectional view taken along the line VIIIVIII of FIGURE 7.

Referring to FIGURES 1 through 3 of the drawings, there is illustrated arefrigerator constructed in accordance with the principles of theinvention. An arrangement illustrated comprises a refrigerator housingassembly of the conventional construction generally designated by thereference numeral 10 and including an outer housing 12 and an innerhousing 14 disposed within the outer housing to form a closed spacetherebetween in which any suitable thermally insulating material 16 isfilled. The outer and inner housings 12 and 14 respectively may be madeof any suitable metallic material such as sheet steel and the thermallyinsulating material 16 may be, for example, glass fibers. A doorgenerally designated by the reference numeral 18 is hinged at one edgeto the housing assembly 10 to open and close the front opening of thelatter and also includes an outer and an inner panel 20 and 22respectively to form a closed space therebetween in which any suitablethermally insulating material 24 such as glass fibers is filled. Bothpanels 20 and 22 may be of the same material as that of the housings 12and 14. In order to ensure that the door 18 hermetically closes thefront opening of the housing unit 10, the inner panel 22 is providedthroughout the internal peripheral edge with an annular gasket 26adapted to abut against the corresponding peripheral edge of the fronthousing opening when the door 18 is in its closed position.

An evaporator 28 in the form of a hollow rectangular prism is suspendedon the upper portion of the inner housing 14 by the internal top wall ofthe latter through fittings 30, 30 and its interior provides a freezingor refrigerating space generally designated by the reference numeral 32and maintained at a temperature sufficient to store refrigerated food.The remaining portion of the inner housing 14 provides a food storagechamber generally designated by the reference numeral 34 and adapted tostore ordinary food not required to be frozen therein. In order tomaintain the freezing space 32 at a low temperature a relatively thicklayer 36 of any suitable thermally insulating material such as foampolyurethane is suitable disposed below the evaporator 28 locally toheat-insulate the refrigerating space 32 from the food storage chamber34. The layer 36 is shown in FIGURE 2 as being formed of a relativelyshallow tray lined with any suitable sheet metal and also serves toreceive dew drops formed.

In order to cool the interior of the inner housing 14, a cooling systemof the conventional construction is provided comprising a closedmotor-operated compressor 38 disposed in a machine room generallydesignated by the reference numeral 40 on the lowermost portion of thehousing unit 10, and a condenser 42 disposed externally of the housingunit 10 on the rear side. Any suitable refrigerant compressed at anelevated temperature by the compressor 38 passes to the condenser 42where it is condensed. Then the condensed refrigerant flows through anordinary device for suppressing a flow of refrigerant (not shown), intothe evaporator 28 where it is vaporized to cool the interior of theinner housing 14. The vaporized refrigerant returns back to thecompressor 38 in the conventional manner.

As shown in FIGURES l and 2, a control panel 44 is disposed on the rearportion of the top wall surface of the outer housing 12 and includes atemperature control 46 for controlling the operation of the compressor38. The temperature control 46 may be of the bellows type well known inthe art and includes a temperature sensitive drum 48 in initimatecontact with the inner bottom surface of the vaporizer 28 to be held inheat exchange relationship with respect to the latter and an operatingknob 50 mounted on the control panel 44. The temperature control 46 isdesigned and constructed such that it functions to maintain atemperature in the refrigerating space 32 in the order of about l C.while at the same time maintaining a temperature in the food storagechamber 34 in the order of 5 C. To this end the temperature control 46may initiate the operation of the compressor 38 when the temperature ofthe evaporator 28 rises for example to C. and cease the compressor 38when that temperature lowers down to 20 C. for example.

While the arrangement illustrated comprises the freezing space and foodstoring chamber 32 and 34 respectively arranged to be cooled by thesingle evaporator 28 it will be understood that the food storage chamber34 may be cooled by an auxiliary evaporator (not shown) operativelyconnected in series or parallel to the evaporator 28. In the latter caseboth evaporators are completely isolated from each other by any suitablemeans and they have the respective lids of any suitable thermallyinsulating material (not shown) in order to thermally isolate them fromthe surrounding air.

According to the teachings of the invention, the evaporator 28 isprovided in the interior with a thermally insulating case or freezercompartment 52 in the form of a hollow rectangular prism having a singleopen space directed toward the open face of the vaporizer 28 andtherefore of the inner housing 14. In other words the case 52 has anupper wall, two opposed side walls, and the bottom wall with the frontcase open. The case 52 is made of any suitable thermally insulatingmaterial such as foam polystyrene or the like to a wall thickness ofapproximately 15 mm and normally closed by a lid 54 of the samematerials as that of the case hinged at one edge to the case 52 wherebythe interior of the case 52 provides a freezing or refrigerating chamber56 thermally isolated from the refrigerating space 32 as previouslydescribed.

Preferably the thermally insulating case 52 is disposed on the upperportion of the evaporator 28 adjacent one side wall leaving a gap 58between the bottom walls of the case and evaporator for the purpose ofaccommodating one or more ice-making trays 60 in contact with the bottomsurface of the evaporator within the gap as shown in FIGURE 1. In orderfor the thermally insulating case 52 to be detachably secured to theinterior of the evaporator 28, L-shaped brackets 62 are fixed on thatside wall of the evaporator 28 adjacent which the case 52 is to bedisposed and U-shaped hangers 64 are firmly secured on the inner topwall surface of the inner housing 14 at such position that the hangers64 have their lower legs upon which there are positioned the associatedL-shaped ledge 66 fixed on the other side wall of the case 52 asdisposed on the brackets 62.

In the normally cooling operation as previously described in conjunctionwith FIGURE 1, the evaporator 28 refrigerates the refrigerating space 32to a temperature in the order of l5 C. while the compressor 38 isintermittently operated to maintain that temperature under control ofthe temperature control 46. As time goes by, the interior of thethermally insulating case 52 or the refrigerating chamber 56 disposedwithin the space 32 will be gradually cooled due to thermal leakagthrough the walls of the case 52 until it reaches approximately l5 C.substantially equal to the magnitude of temperature in the refrigeratingspace 32. Therefore refrigerated food is now possible to be stored inthe referigerating chamber 56.

After the cooling system has continued to be operated for a longinterval of time, a large amount of frost will be formed on the surfaceof the evaporator resulting in a decrease in cooling effect. This leadsto the necessity of operating defrosting means well known in the artsuch as the hot gas system utilizing the gaseous refrigerant involved ata high temperature from the compressor 38 or the heating systemutilizing heat generated by an electric resistor involved. During thisdefrosting operation the evaporator 28 abruptly rises in surfacetemperature which is accompanied by an increase in temperature withinthe refrigerating space 32. However, the thermally insulating case 52 isdesigned and constructed such that the thermally insulating materialtherefor effectively interrupts heat conduction from the heatedevaporator 28 to the case as well as thermal leakage therebetween isminimized. In addition, an increase in surface temperature of theevaporator due to the defrosting ceases within a short interval of time.These ensure that even during the forcedly defrosting operation thetemperature within the refrigerating chamber 56 remains substantiallyunchanged with the' result that refrigerated food can be safely storedin the refrigerating chamber 56.

Referring now to FIGURES 4 and 5 wherein like reference numeralsdesignate the components corresponding or similar to those shown inFIGURES 1 through 3, there is illustrated a modification of thethermally insulating case. The evaporator 28 is disposed in the innerhousing 14 so as to provide a gap 58 between the outer upper surface ofthe evaporator 28 and the inner top wall surface of the inner housing 14suflicient to accommodate one or more ice-making trays 60 in contactwith the evaporator.,Disposed within the evaporator 28 is a thermallyinsulating case 52 such as previously described extending substantiallythroughout the inside width of the evaporator 28. This measure ensuresthat the refrigerating chamber 56 or the interior of the case has aninternal volume as great as possible permitting a larger amount ofrefrigerated food to be stored in the refrigerating chamber.

The case 52 has a front open face and in mounted at the entire frontperipheral edge to a support place 68 having an opening 70 substantiallyequal in both shape and dimension to the front open case face with bothopen faces substantially aligned with each other. Then the support plate68 is rigidily secured at both ends to the inner side walls of the innerhousing 14 by having L- shaped brackets 72, 72 fixed to both the caseand inner housing. In order to thermally isolate the interior of thethermally insulating case 52 from a cold storage chamber such as thefood storage chamber 34 shown in FIGURES 1 through 3, the front opencase face is closed by an openable lid 54 similar to the lid 54 shown inthe previous figures and hinged at one side edge to the support plate68.

FIGURES 6 through 8 illustrate a thermally insulating case similar tothe case 52 shown in FIGURES 1 through 3 except for a plurality of ventsextending through both side walls thereof. As shown, the case generallydesignated by the reference numeral 52 has an openable, thermallyinsulating lid 54 hinged at one side edge to the front open face and aplurality of vents 74 and 76 extending through the upper and lowerportions of each side wall to permit warm air to leave the case and coldair to enter the case respectively.

As best shown in FIGURE 8, the vents 74 extending through the upperportion of each side case wall each have a diameter gradually decreasingin size or tapered toward the external wall surface thereby to permitreative- 1y warm air to easily leave the case. On the other hand thevents 76 on the lower portion of each side case wall each have adiameter tapered toward the internal wall surface thereby to permit coldair to easily enter the case 52.

With the arrangement illustrated in FIGURES 6 through *8, a portion ofair cooled to a low temperature by the evaporator (not shown in thesefigures) during the normal cooling operation enters the interior of thecase I 52 through the lower vents 76 as shown at the arrows in FIGURE 8thereby to cool its interior or a refrigerating chamber 56 whilerelative warm air positioned on the upper portion of the case 62 leavesit through the upper vents 74 as shown at the arrows in FIGURE 8. Thisprocess it repeated to permit the temperature of the case 52 orrefrigerating chamber to be rapidly decreased to .a magnitude at whichrefrigerated food can be safely stored.

On the other hand, during the defrosting operation and especially duringthe forcedly defrosting operation such as previously described, theevaporator abruptly rises in surface temperature but the thermallyinsulating material for the case 52 is effective for interrupting heatradiated by the heated vaporizer. Also because of the upper vents havingthe diameter tapered toward the external surface of its wall, warm airtending to enter the case 52 from the exterior is permitted onlyto'enter it in an extremely small amount. This ensured that therefrigerated food can be stored in the refrigerating chamber '56 duringthe defrosting operation.

The invention has several advantages. For example the user is notrequired to remove refrigerated food from the present refrigeratorduring the defrosting operation. The defrosting operation is possible tobe performed while the refrigerated food remains stored in therefrigerator without the food melt.

What we claimis:

1. In a refrigerator comprising a housing assembly including an outerhousing, an inner housing disposed within the outer housing to form aclosed space therebetween, and thermally insulating material fillingsaid space, said inner housing having a front open face, a thermallyinsulating door for opening and closing said front open face, and anevaporator in the form of a hollow rectangular prism disposed withinsaid inner housing to form a cooling system along with a compressor anda condenser, the combination of a thermally insulating case composed ofthermally insulating material and formed in a hollow rectangular prismhaving a front open face and a bottom surface, and a thermallyinsulating lid for opening and closing the last-mentioned front openface, said thermally insulating case being positioned within the hollowrectangular prism of the evaporator, said thermally insulating casealong with said thermally insulating lid in its closed positionproviding a refrigerating chamber for storing refrigerated food, saidthermally insulating case being constructed to allow for relatively slowthermal leakage between the thermally insulating case and saidevaporator, whereby the interior of said thermally insulating case maybe cooled when said evaportor is operating in its cooling mode andwhereby the interior of said thermally insulat ing case remains coolerthan the interior of said evaporator and does not defrost when saidrefrigerator is defrosted, means defining a plurality of vents extendingthrough each of the upper and lower portions of each side wall of saidthermally insulating case providing communication from the interior ofsaid case with the exterior of said case, said plurality of ventsextending through the upper portion of each side wall of said thermallyinsulating case having a diameter tapered toward the external wallsurface and a plurality of vents extending through the lower portion ofeach side case wall and having a diameter tapered toward the internalside wall surface.

2. Refrigerating apparatus comprising a housing assembly having heatinsulated walls, a food storage chamber within said housing, means forproviding access to said food storage chamber, cooling system means forcooling said food storage chamber, a freezer compartment adapted tofreeze food, means for providing access to said freezer compartment,evaporator means located entirely exterior of said freezer compartmentfor cooling a space exterior of said freezer compartment to atemperature below that of said food storage chamber, said evaporatormeans being adapted to cool the interior of said freezer compartment,means for slowing the rate of heating within said freezer compartment toa rate below that of the heating of the said space exterior of saidfreezer compartment, and to prevent defrosting within said freezercompartment during a refrigerator defrosting operation, said freezercompartment including a substantially vertically disposed wall, saidmeans for slowing the rate for heating the interior of said freezercompartment below that of said space exterior of said freezercompartment including at least one vent formed in said substantiallyvertically disposed wall near the bottom thereof, said vent providingcommunication from the interior of said freezer compartment to saidspace exterior of said compartment, said vent having a relatively smallmouth opening into the interior of said freezer compartment andgradually enlarging outwardly as it extends through said substantiallyvertically disposed wall to form a mouth opening exteriorly of saidsubstantially vertically disposed wall thatis larger than the mouthopening into the interior of said freezer.

3.;A refrigerating apparatus as set forth in claim 2 wherein said meansfor slowing the rate for heating the interior of said freezercompartment below that of said space exterior of said freezercompartment includes at least one vent formed in said substantiallyvertically disposed wall near the top thereof, said vent fluidlyconmeeting the interior of said freezer compartment to said spaceexterior of said compartment, said vent having a relatively large mouthopening into the interior of said freezer compartment and graduallyenlarging outwardly as it extends through said substantially verticallydisposed wall to form a mouth opening exteriorly of said substantiallyvertically disposed wall that is larger than the mouth opening into theinterior of said freezer.

4. A refrigerating apparatus as set forth in claim 3 wherein saidfreezer compartment includes insulating 7 8 material positioned betweenthe interior of said freezer 2,317,840 4/1943 Wild 62441 compartment andsaid space exterior of said freezer com- 2,617,268 11 /1952 Ashby 1 a1,62\ 441 partment. 2,807,149 9/1957 Williams 62-441 5. A rengerat1ng aaratus as set forth 1n im 3 2,889,693 6/1959 Kurowski 62441 whereln thevent posrtloned near the bottom of said sub- 5 3,283,531 11/1966 Horvayet 62441 the vent positioned near the top of said substantialyverstantially vertically disposed wall slants downwardly and 3,377,9414/1968 Jaremus 62441 tically disposed wall slants upwardly.

LLOYD L. KING, Primary Examiner References Cited UNITED STATES PATENTS2,303,138 11/1942 Philipp 62441 2,317,775 4/1943 King 62-441 10 Us. 01.X.R.

